How Grunting During Tennis Leads To A Flat Belly

It’s going to feel a little silly, but channeling your inner Serena on the tennis court could up your game and help you tone faster. Letting out a grunt will actually give you a stronger serve...and possibly a stronger core, according to a recent study published in the Journal of Strength and Conditioning Research.

Researchers at Hardin-Simmons University in Texas found that tennis players who grunted hit the ball 5 mph faster—and actually activated their obliques and chest muscles more effectively—than when they stayed quiet, says study author and physical therapist Dennis O’Connell. And the benefits of being noisy aren't exclusive to tennis; past research has shown that grunting helps during other kinds of forceful efforts, including performing a deadlift, kicking a soccer ball, or even swinging a golf club.

So how does it work, exactly? Grunting increases muscle recruitment, or the number of muscle fibers that you use in a particular exercise, says O’Connell. As a result, you’re able to generate force more easily and even tone those muscles faster.

“Grunting engages the core musculature, which should enhance the contraction force of associated muscle groups,” says Wayne Westcott, director of exercise science at Quincy College and a Prevention advisor. “Muscles rarely work in isolation, so increased force production in one group typically enables increased force production in other muscles engaged in the movement or action.”

Of course, many people find grunting annoying or even embarrassing, and it’s been discouraged on tennis courts and in gyms. But O’Connell’s newest research suggests that you might not actually have to grunt to get those benefits: Taking a deep breath and forcefully exhaling— basically what you’re doing when you grunt, without the awkward noise—will give you the same boost, he says.